This invention relates to a blue-green emitting halophosphate phosphor activated with divalent europium.
Heretofore, it is known that halophosphate phosphors activated with divalent europium emit or generate blue or blue-green fluorescence, as disclosed in Japanese Patent Publication No. 40604/1971 and U.S. Pat. No. 4,038,204. These phosphors, however, do not possess a satisfactory efficiency and are known to have such disadvantages as large deterioration in baking process in producing fluorescent lamps, or a poor lumen maintenance factor of produced lamps, when they are applied to fluorescent lamps.